Living benthic foraminifera: biogeographical distributions and the significance of rare morphospecies

Abstract

Abstract. Previous studies have investigated regional distribution but this is the first attempt to investigate the global biogeographical distribution of individual morphospecies of living/stained smaller benthic foraminifera. From 8032 samples collected between 1952 and 2011 data have been gathered on the relative abundance of >120 species in five major environments ranging from marsh to deep sea. There is a spectrum of six groups of species with abundance ranging from very high (Group 1) to extremely low (Group 6). In the latter species abundance never reaches 10% of an assemblage and, in many cases, it is only 1–2%. Individual species are shown to occupy a range of environments with very few being confined to a single environment (usually either marsh or deep sea). Some species occur in several oceans while others are confined to just one. There is no correlation between species abundance and being either widely or narrowly distributed. Propagules are the most likely mechanism of dispersal but some narrowly distributed species may not produce them. Generalists may be widely or narrowly distributed but opportunists are likely to be widely distributed. The rare species of Group 6 contribute to high diversity in shelf and deep-sea assemblages. These species may be adapted to minor differences in microhabitats induced by disturbance and patchy food supply. Patterns of biogeography have application to ecology, palaeoecology and taxonomy.

Spatial patterns and diversity of foraminifera from an intermittently closed and open lagoon, Smiths Lake, Australia

“…, Goldstein, 1988, Patterson, 1990, Murray, 2013. The high relative abundance of a small number of taxa, irrespective of overall diversity, is consistent with previous estuarine foraminifera studies (Murray, 2013). The spatial distribution of the two assemblages within the lagoon, with a duospecific assemblage in deeper water and a more diverse shallow water assemblage, is consistent with previous studies .…”

“…, Yassini and Jones, 1989, Yassini and Jones, 1995, Cotter, 1996, Nash et al, 2010 and internationally (e.g. , Goldstein, 1988, Patterson, 1990, Murray, 2013. The high relative abundance of a small number of taxa, irrespective of overall diversity, is consistent with previous estuarine foraminifera studies (Murray, 2013).…”

Quantifying Assemblage Turnover and Species Contributions at Ecologic Boundaries

“…Taldenkova et al [69] found this species to be more abundant in the upper bathyal Holocene of the Arctic Ocean than the latest Pleistocene, and ascribed it to a distal-river group of relatively deep-water species that thrive on slightly altered organic matter and is therefore restricted to areas with periodic delivery of organic matter. Murray [70] noted that M. baarleeanus has been recorded live in all oceans except the Indian Ocean. In ODP Hole 994C this species accounted for >0.02 of the CoBI t across six of the ten PATI boundaries, and was abundant in the early part of PATI-10 and in PATI-5 and PATI-4.…”

Late Holocene palaeoproductivity changes: a multi‐proxy study in the Norwegian Trench and the Skagerrak, North Sea

“…Lake (<2 mL L À1 : Diaz & Rosenberg 1995), despite a contemporary increase in nutrient input from the German Bight (Aure & Magnusson 2008) and simulated high primary productivity (Skogen et al 2004). Furthermore, the above-mentioned agglutinated fauna is strongly dominated by Eggerelloides medius, a species dependent on high-quality (fresh) organic matter and, hence, indicative of high primary productivity (Alve 2010;Murray 2013) rather than of oxygen depletion. The absence of severe oxygen depletion is supported by a relatively low abundance of low oxygen benthic foraminiferal fauna from c. 1700 years BP towards the present (Fig.…”